1. Field of the Invention
The present invention relates to a transposition controller for an electronic musical instrument and, for example, a transposition controller suitably used in an electronic musical instrument which comprises an auto-play unit and can execute an ensemble play.
2. Description of the Related Art
Conventionally, an auto-play unit which records data played by the player in a recording medium and automatically reads out and plays back the recorded play data in accordance with the player's instructions is known. In an electronic musical instrument comprising an auto-play unit of this type, a plurality of concurrent tone generation channels are assigned to a plurality of play parts, and when the player plays a given part with a keyboard while playing back auto-play data, an ensemble play can be realized.
Upon executing such an ensemble play, when the auto-play data is played back to have a chord other than a C chord as a tonic chord, i.e. when the auto-play data was recorded in a key other than the C major key, the player must play the keyboard in the key matched to that of the auto-play data. However, it is generally difficult, especially for a beginner, to play in a key other than the C major key.
Some electronic musical instruments can automatically transpose and generate tones by setting desired transposition information. Therefore, by utilizing this transposition function, even when auto-play data was recorded in a key other than the C major key, the auto-play data can be transposed and played back in the C major key, so that the player can play the keyboard in easy C major key matched to the transposed auto-play data.
However, since the conventional electronic musical instrument transposes the entire parts if the transposition information is set, the keyboard part is undesirably transposed, too. For this reason, even when the player plays the keyboard part in the C major key in correspondence with the key of the transposed auto-play data, since note data (play data) from the keyboard itself is transposed, the key of auto-play part and the key of the keyboard part become different from each other.